I'd say all programmers of any significant experience know the concept of polymorphism, but it's quite possible to know the concept without knowing the word. T

I'd say all programmers of any significant experience know the concept of polymorphism, but it's quite possible to know the concept without knowing the word. They might be using discriminated unions, or type-distinguishing enums on rows or structs with a superset of attributes, but the concept is hard to avoid when trying to generalize behaviour over heterogeneous data.